We believe that the bug you reported is fixed in the latest version of
ruby1.8, which is due to be installed in the Debian FTP archive:

irb1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/irb1.8_1.8.1+1.8.2pre3-2_all.deb
libbigdecimal-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libbigdecimal-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libcurses-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libcurses-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libdl-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libdl-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libdrb-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libdrb-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
liberb-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/liberb-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libgdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libgdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libiconv-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libiconv-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libopenssl-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libopenssl-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libpty-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libpty-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libracc-runtime-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libracc-runtime-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libreadline-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libreadline-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
librexml-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/librexml-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libruby1.8-dbg_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libruby1.8-dbg_1.8.1+1.8.2pre3-2_i386.deb
libruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libsdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libsdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libsoap-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libsoap-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libstrscan-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libstrscan-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libsyslog-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libsyslog-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libtcltk-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libtcltk-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libtest-unit-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libtest-unit-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libtk-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libtk-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libwebrick-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libwebrick-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libxmlrpc-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libxmlrpc-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libyaml-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libyaml-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libzlib-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libzlib-ruby1.8_1.8.1+1.8.2pre3-2_i386...

We believe that the bug you reported is fixed in the latest version of
ruby1.8, which is due to be installed in the Debian FTP archive:

irb1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/irb1.8_1.8.1+1.8.2pre3-2_all.deb
libbigdecimal-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libbigdecimal-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libcurses-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libcurses-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libdl-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libdl-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libdrb-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libdrb-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
liberb-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/liberb-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libgdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libgdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libiconv-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libiconv-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libopenssl-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libopenssl-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libpty-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libpty-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libracc-runtime-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libracc-runtime-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libreadline-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libreadline-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
librexml-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/librexml-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libruby1.8-dbg_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libruby1.8-dbg_1.8.1+1.8.2pre3-2_i386.deb
libruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libsdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libsdbm-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libsoap-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libsoap-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libstrscan-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libstrscan-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libsyslog-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libsyslog-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libtcltk-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libtcltk-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libtest-unit-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libtest-unit-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libtk-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
to pool/main/r/ruby1.8/libtk-ruby1.8_1.8.1+1.8.2pre3-2_i386.deb
libwebrick-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libwebrick-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
libxmlrpc-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
to pool/main/r/ruby1.8/libxmlrpc-ruby1.8_1.8.1+1.8.2pre3-2_all.deb
...